1. Field of the Invention
The present invention relates to a method for producing an image-forming apparatus while keeping the inside in a pressure-reduced state. Particularly, the invention relates to a method for producing the image-forming apparatus while wires used in the image-forming apparatus are formed by sintering particles of an electric conductor. The invention further concerns the image-forming apparatus produced using the production method.
2. Related Background Art
Cathode-ray tubes (CRTs) are popularly and generally used as the image-forming apparatus at present. Recently, the large cathode-ray tubes with the display screen over 30 inches also came on the market. In order to increase the size of the display screen in the case of the cathode-ray tubes, however, there arise problems that the depth dimension thereof must be increased according to the increase of the screen size and that the weight also becomes greater according to the increase of the screen size.
In order to meet the consumer's desires for images of strong appeal on a larger screen, the cathode-ray tubes thus require a larger placement space and thus are not always suitable for realizing the increase of the screen size.
There are thus expectations for the debut of a flat image display apparatus that is thin enough to be hung on a wall, that is of low power consumption, and that has a thin, lightweight, large screen, in place of the large and heavy cathode-ray tubes (CRTs). Research and development is active on liquid-crystal display devices (LCDs) as such flat image display apparatus.
Since the above LCDs are not of an emissive type, they require a light source called a back light. They thus had a problem that most of the power consumption was due to lighting of the back light. Further, the LCDs still have problems that the image is dark because of low utilization efficiency of light, there is a limit to viewing angles, it is difficult to realize a large screen over 20 inches, and so on.
An emissive type flat image display apparatus is thus drawing attention instead of the LCDs having the above problems. Examples of such display apparatus proposed heretofore are, for example, plasma display panels (PDPs) arranged to emit light by irradiating a fluorescent material with ultraviolet light to excite the fluorescent material, flat panel displays arranged to emit light by irradiating the fluorescent material with electrons emitted from electron-emitting devices to excite the fluorescent material, and so on.
With the displays using the electron-emitting devices, the fluorescent material is made to emit light when the fluorescent material is irradiated with electrons emitted from the devices under reduced pressure. Therefore, the light emission mechanism thereof is thus basically the same as in the case of the CRTs. This permits us to expect high-luminance displays without viewing angle dependence.
Such electron-emitting devices are generally classified into cold cathodes and thermionic cathodes. Further, the cold cathodes include field emission type electron-emitting device (hereinafter referred to as “FE”), electron-emitting device comprised of a stack of metal layer/insulating layer/metal layer (hereinafter referred to as “MIM”), surface conduction electron-emitting device, and so on.
In the image display apparatus using the above electron-emitting devices, the devices need to operate in an airtight vessel maintained, for example, under a pressure lower than 10−4 Pa.
The image display apparatus using the surface conduction electron-emitting devices among the above cold cathode is disclosed, for example, in Japanese Patent Applications Laid-Open No. 6-342636, No. 7-181901, No. 8-034110, No. 8-045448, No. 9-277586, and so on.
FIG. 5 and FIG. 6 show the schematic structure of an example of the surface conduction electron-emitting devices disclosed in the above applications. FIG. 7 is a diagram to show the schematic structure of an example of the image display apparatus using the surface conduction electron-emitting devices disclosed in the above applications.
FIG. 5 is a plan view of the surface conduction electron-emitting device and FIG. 6 is a cross-sectional view of the surface conduction electron-emitting device. In FIG. 5 and FIG. 6, reference numeral 101 designates an insulating substrate, 104 an electroconductive film, 102 and 103 electrodes, and 105 an electron-emitting region. The electron-emitting region 105 has a gap. When a voltage is placed between the electrodes 102, 103, the electron-emitting region 105 emits electrons.
In FIG. 7 numeral 5005 denotes a rear plate, 5006 an outer frame, and 5007 a face plate. Joint (Sealing) portions between the outer frame 5006, the rear plate 5005, and the face plate 5007 are joined (or sealed) to each other with a bonding material such as a low-melting-point glass frit or the like not illustrated, thereby composing an airtight vessel 170 for maintaining the inside of the image display apparatus in vacuum. The surface conduction electron-emitting devices 5002 are formed in an array of N×M on the rear plate 5005 (where N and M are positive integers not less than 2 and are properly determined according to the number of display pixels aimed). A fluorescent material is opposed to the electron-emitting devices.
The electron-emitting devices 5002 are wired in a matrix by M column-directional wires 107 and N row-directional wires 106, as illustrated in FIG. 7. In the case of this wiring in the matrix, insulating layers, not illustrated, are placed for electrically insulating the two types of wires from each other, at least, at intersecting portions between the row-directional wires and the column-directional wires.
A fluorescent film 5008 comprised of the fluorescent material is formed on the lower surface of the face plate 5007. A metal back 5009 of Al or the like is formed on the rear-plate-side surface of the fluorescent film 5008.
In the case of color display, fluorescent materials (not illustrated) of the three primary colors, red (R), green (G), and blue (B), are laid separately. Further, a black material (not illustrated) is laid between the fluorescent materials of the respective colors forming the fluorescent film 5008.
The inside of the above airtight vessel is maintained in a vacuum of the pressure lower than 10−4 Pa. The distance between the rear plate 5005 with the electron-emitting devices formed thereon and the face plate 5007 with the fluorescent film formed thereon, as described above, is usually kept in the range of several hundred μm to several mm.
A method for driving the image-forming apparatus described above is as follows. A voltage is applied to each electron-emitting device 5002 via terminals Dx1 to Dxm, Dy1 to Dyn outside the vessel, and via the wires 106, 107, whereby each device 5002 emits electrons. At the same time as it, a high voltage of several hundred V to several kV is applied to the metal back 5009 via a terminal Hv outside the vessel. This accelerates the electrons emitted from each device 5002 to make them collide with the corresponding fluorescent material of each color. On this occasion the fluorescent material is excited to emit light, thus displaying an image.